toilet tank intermittently would not fill

My toilet is. flushing fine but sometimes tank will not refill with water after flushing. I have to turn off the water valve and turn it back on before tank will refill again. This happens a few times everyday and I cant figure out a permanent fix. Pls help!

toilet tank intermittently would not fill

if it's a fluidmaster just replace the small rubber seal/diaphragm. The rubber hardens after a few years. It's about a two minute job, no tools required. The last one i bought was $1.35 a couple of weeks ago. It's just about the only thing that ever goes bad with a fluidmaster. They are the best IMO